Electric telephone-transmitter.



No. 689,503. Patented Dec. 24, I90I.

A. M. MASSARI. ELECTRIC TELEPHU'NE TRANSMITTER. (Application md Feb. 1s, 1899.)

(No Mudel.)

` WJTNESSES i INVENTOR4 Attorney NITED STATES V"AfrEN-T Fries'.

ALFONSO MARIA MASSARI, OF ROME, ITALY.

ELECTRIC TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 689,503, dated December 24, 1901. Application led February 18. 1899. Serial No. 706,071. (No model.)

To all whont it may concer-1t:

Be it known that I, ALFONSO M. MAssARI, commandant in the Italian Naval Reserve, residing at 163 Via Torino, Rome, Italy, have invented certain new and useful' Improvements in Electrical Telephone-Transmitters, of which the following is a specification, reference being had therein to the accompanying drawings.

My invention relates to electric telephonetransmitters, and has for its object an efficient transmitting instrument of simple construction that can be readily repaired when necessary and in which the transmission can be very delicately regulated.

Figure' 1 is a side elevation, partly in section; and Fig. 2 is an end elevation of an instrument made according to my invention.

A is a plate of insulating material, preferably of ebonite, having a central opening therein and having the sleeves a a formed on or attached thereto. B is the mouthpieceof the instrument and is removably attached to the insulating-sleeve a, preferably by means of screws b. C is a hollow metal cylinder, which has an annular groove c on itssouter periphery and has an internal recess formed at one end thereof, which fits overthe-insulating-sleeve cb and is secured thereto. D is a tube having its free end screw-threaded. d is a disk or flat ring having a central opening therein to which one end of the tube D is attached, and d is a short hollow cylinder attached to the edge of the dat ring or disk d. The tube D, ring or disk d, and cylinder d' are of brass or other suitable conducting material and may beintegral. The tube D passes through the plate A and cylinder C and has its screw-threaded end projecting beyond the latter. S is a coiled spring situated between the ring or disk dand a shoulder formed by the aforesaid internal recess in the cylinder O. All these parts are mounted on the baseboard P. Y

d2 is a nut screwed onto the free end of tube D, and d3 is a lock-nut for securing the said nut in position.

The cylinder CZ contains a carbon block or cup E, situated opposite the central opening in the ring or disk d and held in position and insulated by chalk F.

fis a piece of cotton or vfelt placed in the carbon cup F..

f' is a ring of cotton, and eis granulated carbon.

H is the diaphragm, and I is an elastic ring or tube of rubber or of other soft and insulating material which separates and insulates the diaphragm from the mouthpiece.

a? is an insulating-sleeve, preferably of ebonite, which fits into the tube D and has an annular flange a4 at its outer end. 4

g g represent a metal rod which passes through the sleeve a2 and bears against the Y carbon block E, and g is a nut for regulating the length of the rod g.'

R is a sliding piece of metal having a longitudinal slot r therein. r is a screw secured to the base P and on which the piece E slides. This sliding piece R has a knob or handle r2 at one end thereof and has its opposite end forked, so as to slide intothe groove c on the cylinder C, and thus secure the instrumentl to the base P.v The ends of the fork are recessed and fit onto the screws r3 when in depressed position. One end T of the'line-wire is attached td the sliding piece R, and the other wire T is attached to a contact-piece t, whichbears on the metal rod g. The electric current is thus connected through the sliding piece R, cylinder O, tube D, ring or disk d, and the cylinder cl and through the rod g, carbon block E, and' granulated carbon e, so that diaphragm H completes the circuit and by the variation of pressure, as usual, makes the necessary variations for transmission of sounds. When not in use, the diaphragm is supported between the cotton or felt pieces ff' and the rubber ring I. In Fig. I the parts are shown as slightly separated for clearness of illustration; but it Will be understood that in actual use they are brought into contact. When the instrument is in use, the diaphragm vibrates, and in so doing varies the pressure of contact with the cylinder d'. The spring S normally tends to press the cylinder d', ring or disk d, and tube D toward the diaphragm. The nut d2 acts against the pressure of this spring and bears against the free end of the cylinder C. The transmission is regulated by adjusting the pressure on the diaphragm,

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and this is eected by screwing up or unscrewing the nut d2 and its washer d3, and thus respectively decreasing or increasing the pressure on the diaphragm, by which means a very delicate adjustment can be effected. The spring S tends to press ring or disk d and flange d toward the diaphragm against the packing I; but by means of the die or nut d2 engaging the tube D said disk may be held so as to bear with a greater or less pressure against the diaphragm.

In telephone-transmitters in which granulated carbon is used, as described, it sometimes happens that from a sudden shock or other cause the granulated carbon becomes displaced and a part of it finds its way between the cotton Wool and diaphragm to the cylinder d', thus making contact and rendering the transmitters useless. Should this happen in the case of an instrument made according to my invention, the latter may be quickly and easily repaired by means of removing the screws h, when the mouthpiece B and diaphragm II can also be removed, the granulated carbon replaced, and these parts readjusted. By means of attaching the mouthpiece to the insulating-ring c and also insulatingfrom the diaphragm by means of the rubber or like ring or tube I it is possible toI certained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is l. In a telephone-transmitter of the character described, the mouthpiece iiorrning a front support, an insulating-ring, and a diaphragm in position to bear against said ring when pressed against the same, a hollow metallic cylinder bearing against the rear face near the outer edge of said diaphragm, and a spring tending to press said cylinder against the diaphragm, all combined substantially as described.

2. In a telephone-transmitter as described, the mouthpiece, a non-conducting ring behind said mouthpiece, the diaphragm having its front face resting against said ring when clamped, an annular metallic piece or hollow cylinder bearing against the rear face of the diaphragm, a spring by which said hollow cylinder is pressed toward the diaphragm, and means for limiting the forward position of the hollow cylinder, all combined substantially as described.

3. In a telephone-transmitter, the mouth# piece and an insulating-ring behind the same, the diaphragm and a metallic ring bearing against the same near the outer edge thereof, a iiat metallic ring connected to the said metallic ring, and a metallic tube connected to the inner edge of said flat ring, a spring bearing on the flat ring to press the same and its connected ring toward the diaphragm, and a collar supporting the tube and a nut engaging said tube and. collar, and serving to adjust the position of the ring which,.bears on the diaphragm, all combined substantially as described.

4. In a telephone-transmitter, the mouthpiece, diaphragm, and a metallic ring or hollow cylinder adjustable against the rear face of the diaphragm near the outer edge thereof, a carbon cup having its edge in contact with the rear face of the diaphragm, and an. insulated metallic rod held by spring-pressure against the bottom of said carbon cup, the

outer metallic ring being in electrical connection with one terminal, and the insulated rod with the otherterminal, all combined substantially as described.

5. In a telephone-transmitter, the mouthpiece removable from the front, the diaphragm clamped against the rear face of the mouthpiece by an adjustable ring, a carbon cup having its edge against the rear face of the diaphragm Within the adjustable ring, and a spring-pressed rod bearing against the center of said carbon cup, all combined substantially as described. l

G. In a telephone-transmitter, the diaphragm supported at the edge and removable from the front, a carbon cup having its edge against the rear face of the diaphragm, a packing of felt or like material Within and without the carbon cup and bearing on the diaphragm, and an insulating-support of chalk surrounding the base of the carbon cup, all combined.

7. In a telephone-transmitter, the base or support having a hole therein, a hollowmetallic cylinder in said hole in the base, and supporting the operating mechanism of the phone, a groove in said cylinder in rear of the base, andV a sliding fork engaging said groove, whereby the fork may clamp the phone to its base, or permit its removal from the front thereof, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

ALFONSO M. MASSARI.

Vitnesses:

LEWIS MORRIS IDDINGs, Aars'roDEMo RAGGI.

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